multi_speaker.py: Tracks up to 2 speakers simultaneously. When 2 distinct
DoA angles are detected (30°+ apart) for >1s, locks the XVF3800's fixed
beams onto each speaker. Releases back to auto mode when only 1 speaker
remains (3s timeout). Manages beam gating so only the speaking beam is active.
xvf3800.py: Added beam steering commands — enable_fixed_beams(),
set_beam_azimuths(), enable_beam_gating(), read_all_beams().
Manager gets steer_beams() and release_beams() convenience methods.
headmic.py: Wire multi-speaker tracker into DoA loop. New endpoint:
GET /speakers/tracked — current speaker positions, beam mode, lock state.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
